TABLE 2.3 Representative Functional Groups and the Compounds in Which They Are Found Name of Biological Name of Biological Structure Group Importance Structure Group Importance R-O-H Alcohol Lipids, carbohydates Ether Archaea plasma membranes Aldehyde* Reducing sugars such as glucose; polysaccharides Sulfhydryl Energy metabolism; Ketone* Metabolic protein structure intermediates Carboxyl Organic acids, Methyl DNA;energy OH lipids,proteins metabolism R=O-P-O Phosphate ATP DNA -NH2 Amino Proteins *In an aldehyde,a C-O is at the end of a molecule, in contrast to the internal C=O in a ketone. Ester Bacteria and eukaryotic plasma membranes Table 2.3.1Table 2.3.1